BLS, of course, does its very best job to stay on top of these numbers. But it's entirely possible almost guaranteed that they're going to get them wrong, either by being too positive (entirely likely) or too negative (one can hope, but don't hold your breath.)

Speaking of the BLS numbers.... Riddle me this, according to BLS there're 82,000 chemists, there're probably around 23,000 grad students and 5,000 postdocs (from 2009 data), so 110,000 altogether. Let's assume that 50% of them are ACS members, that's 55,000. ACS has 164,000 members, who are the other 109,000?

"Chemist" does not encompass everyone with a chemistry degree. Professors aren't chemists, biologists aren't chemists, all the sales people, tech support, etc. aren't chemists according to the BLS, but all can be ACS members.